The “Bike Yield Law” proposed by Supervisor John Avalos is poised to be approved by the Board of Supervisors.

The ordinance urges the SFPD to let bicycle riders safely treat stop signs as yield signs. Avalos plans to introduce the ordinance tomorrow, and it has support from six supervisors — the majority needed to vote it into law. It’s unclear if it has support from SFPD officials.

The latest endorsements come from Supervisors David Campos, Jane Kim, and Eric Mar, joining early sponsors London Breed and Scott Wiener. The six co-sponsors plan to hold a press conference at City Hall before tomorrow’s board meeting.

At the event, SF Bicycle Coalition Executive Director Noah Budnick will speak about “the need to provide SFPD the direction and clarity that they deserve in order to achieve Vision Zero and safer streets overall,” according to an SFBC press release.

While local legislation cannot supersede the state’s stop sign law, Avalos’s ordinance would set a “San Francisco Right-of-Way Policy” that would “make citations for bicyclists who safely yield at stop signs the lowest law enforcement priority.” In essence, it would legitimize the safe, practical way that people on bikes normally treat stop signs, which has been legal in Idaho for 32 years.

Avalos announced his plans to introduce the legislation last month after SFPD Park Station Captain John Sanford called off his letter-of-the-law crackdown on bike commuters rolling stop signs. In an interview with Streetsblog, Sanford seemed hesitant to support the bill, saying that police already use discretion in prioritizing limited enforcement resources.

Support from the SFPD will be crucial for the non-binding ordinance to hold sway over police traffic enforcement priorities. The SFPD’s lagging compliance with its own “Focus on the Five” campaign against the most dangerous driving violations is evidence of how difficult it is to change police practices, even when it’s official department policy. Most SFPD stations have only begun to move toward the enforcement target set in January 2014.

The press conference announcing the “Bike Yield Law” ordinance will be held tomorrow on the steps of City Hall at 12:30 p.m.